The present invention relates to batteries which can be energized and activated by sea water and more particularly batteries for equipping radio-sonic buoys used for hydrolocation purposes.
Normally such batteries have elements located in an insulating case containing the openings necessary for the inflow of water and the giving off of gas. It is known that each element is constituted by two electrodes, called the anode and the cathode. The elements are electrically connected in series in such a way that the anode of one element is connected to the cathode of the adjacent element.
On putting into service by immersion the electrolyte, generally sea water, passes between the electrodes by means of outwardly directed openings provided level with each element, Thus, in the surrounding conductive electrolyte an electrical path is created between the electrodes of one random element and the electrodes of each of the other elements. As the electrodes are at different potentials to one another electrical leakage currents occur between any random one of the electrodes and each of the other electrodes.
U.S. Pat. No. 3,394,034, published on July 23, 1968 describes batteries which can be energized by sea water. Each element has a plug or cap making it possible to seal the element when the plug or cap is closed. The latter can be opened for brief periods during the operation of the battery to permit the introduction of the electrolyte, its replacement and the removal of gas given off.
Although these batteries have an increased service life, they have the disadvantage of using relatively complex devices which are not really compatible with the requirements of mass production at minimum cost.
There are other simpler batteries for which the openings made in the case cannot be closed. The electrolye is allowed to freely circulate between the elements and between the interior of the battery and the exterior. The electrical leakage currents between the elements passing via the electrolyte are then generally high and give rise to accelerated wear of the electrodes, reducing the service life of the pile.
To compensate this wear it is indispensible to increase the quantity of metal forming the electrodes to have an acceptable life. This is a disadvantage, because the metals used for the electrodes are costly, which increases the cost of the equipment.